maxfarmor
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Hi
I'm working on a problem here and i'm still quite new to electronics however i read up as much as i can everyday while waiting for my parts to arrive by mail. In the project ( a multi stage coilgun) i need to switch a coil on using a "dark sensor" when the bullet blocks the light coming to the sensor in question. the coil will receive about 200A current and should be active for some milliseconds before deactivating. I would also wish for it to activate/deactivate as fast as possible.
My current idea is this : the current from the battery goes through a switch (regulated by the sensor) then through the coil and back into the battery with proper resistances in between to get the current i need. As i understand MOSFETs and IGBTs would both work but i cant figure out the real difference between the two. Also there seems to be several different "light sensors" (photodiodes, photoresistors and phototransistors at least) do these have different areas of operation, that is, is one more suited to my problem than another? Finally, as i understand the coil will contain energy in its magnetic field which will then induct a large current in the coil even after the power has been switched off. How can i quickly dissipate this current? I read somewhere that you can put a diode in series with a high resistor to allow the current to dissipate quickly but im unsure where it should be placed.
And another question, if i buy a switch rated for, say 50W and the current will produce much more in it, will it work because the pulses are so short that it wont have time to get heated up? are the power ratings meant for continuous day long use and so, can they actually tolerate brief high-intensity work?
The battery is a 22.2V 3300mAh 60C LiPo battery.
thank you for your time
-Max
I'm working on a problem here and i'm still quite new to electronics however i read up as much as i can everyday while waiting for my parts to arrive by mail. In the project ( a multi stage coilgun) i need to switch a coil on using a "dark sensor" when the bullet blocks the light coming to the sensor in question. the coil will receive about 200A current and should be active for some milliseconds before deactivating. I would also wish for it to activate/deactivate as fast as possible.
My current idea is this : the current from the battery goes through a switch (regulated by the sensor) then through the coil and back into the battery with proper resistances in between to get the current i need. As i understand MOSFETs and IGBTs would both work but i cant figure out the real difference between the two. Also there seems to be several different "light sensors" (photodiodes, photoresistors and phototransistors at least) do these have different areas of operation, that is, is one more suited to my problem than another? Finally, as i understand the coil will contain energy in its magnetic field which will then induct a large current in the coil even after the power has been switched off. How can i quickly dissipate this current? I read somewhere that you can put a diode in series with a high resistor to allow the current to dissipate quickly but im unsure where it should be placed.
And another question, if i buy a switch rated for, say 50W and the current will produce much more in it, will it work because the pulses are so short that it wont have time to get heated up? are the power ratings meant for continuous day long use and so, can they actually tolerate brief high-intensity work?
The battery is a 22.2V 3300mAh 60C LiPo battery.
thank you for your time
-Max
